Integrated circuit device and microprocessor constituted thereby

摘要

An integrated circuit device in which by connecting signal pads of a semiconductor chip to either a power potential lead or a ground potential lead of a package at assembly time, either of plural initial states set in the semiconductor chip in advance is set, and a microprocessor constituted by above-mentioned integrated circuit device in which a signal for setting an initial value of a data bus width control resister at resetting timing is inputted from a data size designating pad and set, and a register for controlling an effective data bus width is provided, and by changing the set value of the data bus width register by the instruction, an effective bit width of the data bus is changed to the value different from the initial set value, thereby the instruction under pre-processing as the pipeline processing is cleared, and the instruction right after is fetched at the effective bus width newly set for execution.